The present invention relates to a system for monitoring personal exposure to carbon monoxide. In the system of the present invention, carbon monoxide is oxidized by alumina impregnated with silver ion and permanganate ion, the oxidation resulting in the impregnated alumina changing color from purple to brown.
Commercial devices in the form of indicator tubes for monitoring personal exposure to various toxic gases or vapors are well known. An indicator tube is a glass tube containing a granular chemical and is worn by the user in a position close to his breathing zone. A pump connected to the tube pulls air from the atmosphere through the tube. The granular material reacts chemically with the toxic gas and a color change occurs. The color change progresses from the entrance to the exit of the tube as the various cross sectional layers react. At the end of any given sampling period, the length of the color change stain in the tube is proportional to the concentration of the toxic gas averaged over the sampling period.
Prior workers have reported in the literature that silver permanganate, when coated on various porous substrates, will produce materials which oxidize carbon monoxide in the ambient atmosphere. See, for example, M. Katz and S. Halpern, "Oxidation of Carbon Monoxide in Air by Silver Permanganate", Ind. & Eng. Chem., Vol. 42, p. 345 (1950).